Log Out Link isn't working
 

I have moved the log out link from the navbar into the Quick Links menu. Here's its code:
Code:
$vbphrase[log_out_x]
But it doesn't work. When I click the link, the popup appears, asking me if I am sure I want to log out. I click "Ok" and the popup goes away and nothing happens - the page just stays as if nothing happened.

Why is this?